Java Program to Add two Numbers

Sum of two numbers :

public class JavaExample {
  public static void main(String[] args) {
    // two integer variables with values
    // and a variable "sum" to store the result
    int num1 = 5, num2 = 15,sum;

    //calculating the sum of num1 and num2 and
    //storing the result in the variable sum
    sum = num1+num2;

    //printing the result
    System.out.println("Sum of "+num1+" and "+num2+" is: "+sum);
  }
}

Sum of 5 and 15 is: 20

Sum of two numbers using Scanner :

import java.util.Scanner;
public class AddTwoNumbers2 {

    public static void main(String[] args) {
        
        int num1, num2, sum;
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter First Number: ");
        num1 = sc.nextInt();
        
        System.out.println("Enter Second Number: ");
        num2 = sc.nextInt();
        
        sc.close();
        sum = num1 + num2;
        System.out.println("Sum of these numbers: "+sum);
    }
}

In this program, the statement Scanner sc = new Scanner(System.in); creates an instance of Scanner class. This instance calls nextInt() method to read the number entered by user. The read values are stored in variables num1 and num2. Once the values are stored in variables. The addition is performed on these variables and result is displayed.

Enter First Number: 
7
Enter Second Number: 14
Sum of these numbers: 21

Program to add two non-integer numbers :

import java.util.Scanner;
public class JavaExample {

  public static void main(String[] args) {

    double num1, num2, sum;
    Scanner sc = new Scanner(System.in);
    System.out.print("Enter First Number: ");
    num1 = sc.nextDouble();

    System.out.print("Enter Second Number: ");
    num2 = sc.nextDouble();

    sc.close();
    sum = num1 + num2;
    System.out.println("Sum of "+num1+" and "+num2+" is: "+sum);
  }
}​

Output :

Enter First Number: 14
Enter Second Number: 20
Sum of 14.0 and 20.0 is: 34.0